package com.rightsidetech.commom.utils;

import org.springframework.web.multipart.MultipartFile;

import java.io.FileInputStream;
import java.math.BigInteger;
import java.security.MessageDigest;

public class MD5Files {
    private static  final  int NEGATIVE_ONE=-1;
    public static String getFileMD5(MultipartFile multipartFile) {
        if (multipartFile==null) {
            return null;
        }
        MessageDigest digest = null;
        FileInputStream in = null;
        byte buffer[] = new byte[1024];
        int len;
        try {
            digest = MessageDigest.getInstance("MD5");
            in = (FileInputStream) multipartFile.getInputStream();
            while ((len = in.read(buffer, 0, 1024)) != NEGATIVE_ONE) {
                digest.update(buffer, 0, len);
            }
            in.close();
        } catch (Exception e) {
            e.printStackTrace();
            return null;
        }
        BigInteger bigInt = new BigInteger(1, digest.digest());
        return bigInt.toString(16);
    }

}
